This invention relates generally to a fastener of the screw type used in conventional applications to hold structural elements or components in position relative to each other and more particularly, to a self-aligning threaded screw which reduces the danger of cross-threading when the screw is inserted into a mating tapped hole or threaded nut. Generally, there is no difficulty in starting a threaded machine screw in a tapped hole or nut when the two mating parts meet with the longitudinal axes in alignment. However, when the screw meets the entrance to the tapped hole with a mis-alignment between the longitudinal axes, the person directing the screw begins a process, perhaps even subconsciously, of "jiggling" the screw to start the threading process. A grossly mis-aligned screw quickly informs the person of the unacceptable condition and adjustment is made. However, a slight mis-alignment can easily allow the start of an engagement between the threads which results in cross-threading, wherein the threads on the screw or in the tapped hole or both are damaged. In severe cases, the hole may need retapping and the screw may have to be discarded. Thus, losses, especially in mass production with highly repetitive operations, can be worthy of attention both in terms of lost time and direct material costs.
What is needed is a screw fastener which performs the conventional functions of such machine type fasteners and minimizes or eliminates the loss and waste associated with mis-alignment and cross-threading.